To explore the phenomena of the plasma-propellant interaction (PPI) and to point out the role of radiation, a series of experiments have been performed at the U.S. Army Research Laboratory. For this, the plasma radiation to the propellant has been separated from all other energy transfer mechanisms. The results clearly indicate that the observed structural damage of translucent JA2 samples is due to radiation only. An other aim of this work is to clarify some misunderstandings in analyzing plasma-propellant interaction. By variation of the electrical pulse length it will be shown that electrical energy is in no way a useful parameter to characterize propellant response to variable plasma igniter systems.